💎 Scientists from Skoltech and MISIS University have solved the "diamond paradox." Researcher shave figured out why graphite doesn't form the familiar cubic diamond under high pressure. Instead, it creates a hexagonal form known as lonsdaleite. While cubic diamond is thermodynamically more stable, at the nanoscale, a lonsdaleite nucleus fits much more easily into the graphite matrix: its formation barrier is twice as low, and it requires up to three times fewer atoms to start growing. As it expands, this intermediate crystal can either transform into a standard diamond or remain as lonsdaleite. Understanding this mechanism helps researchers better control the synthesis of superhard materials and model high-pressure processes deep inside planets. The findings are published in the journal Carbon.